A computerized method for flow-induced random vibration analysis of nuclear reactor internals

The general analytical, numerical, and programming techniques of a computerized method for flow-induced random vibration analysis of nuclear reactor internal components is discussed. The statistical approach used is similar to that originally introduced by Powell and subsequently applied to predict the response of flat plates to homogeneous turbulent air flow. The imput damping ratios and parameters related to the flow field are assumed to be known from experimental data, while the virtual mass and natural frequency shift effects due to hydraulic loading of the structure are included in the analysis. The latest numerical techniques developed for use with modern, high-speed digital computers are employed to evaluate the acceptance integrals, thus permitting the basic method to be applied to the vibration analysis of complex structures excited by inhomogeneous turbulent flow - a situation that is commonly encountered inside a nuclear reactor. The importance of computer program modulization and its relationship to overlays are discussed. Some representative predicted vibration amplitudes based on a typical pressurized water reactor design are given. (Auth.)